1. Field of the Invention
The present invention relates to a rod handle and to a process and an apparatus for providing a protective cover on a rod-like structure, more particularly an injection molding process and apparatus for applying a protective coat on a handle portion of a broomstick or the like.
2. Description of the Related Art
It is often desirable to provide a resilient and smooth protective cover over the handle portion of a broomstick or the like so as to make handling of the item more comfortable. Numerous protective covers for broomsticks are available on the market today. Some of these covers are produced by injecting a two-component polyurethane into a mold containing the handle portion of the broomstick. The injected polyurethane components then react and bond with each other to form a protective coat over the broomstick portion. The cured polyurethane is characterized by an open or close-celled structure.
This production technique is rarely used by the industry because the bond-forming process is slow as it takes a long time to cure and deposit the desired thickness of the two component polyurethane over the broomstick portion. Other disadvantages associated with this method are: (1) the high cost of the raw materials, and (2) the polyurethane has a low level of resistance to wear and tear, due to its cell-type structure.
Another production technique for producing a protective cover for the handle or grip area requires the manufacture of a thin tubular sleeve and then fitting the sleeve over the grip area of the broomstick. This technique is also expensive and, over an extended period of use, the sleeve becomes loose and sloppy.
An object of the present invention is accordingly to provide a low-cost method and an apparatus for producing a durable protective coat for a handle portion of a rod-like structure such, for example, as a broomstick without the aforementioned disadvantages, and to provide a rod handle in accordance therewith.
In one embodiment of the present invention, the process includes the steps of: (1) placing the rod-like handle concentrically within a cavity of a mold with projections extending from an inside wall of the mold and toward the rod-like handle, and (2) injecting a thermoplastic resin such, for example, as polypropylene, thermoplastic synthetic rubber or the like into the mold. Advantageously, the projections serve as breaking points to counteract forces imparted during the injection cycle, so as to avoid deforming the rod-like handle.
In another embodiment of the present invention, one end of the handle is placed inside the mold wherein the injected material settles, surrounds and bonds to said one end of the handle. Where the handle is constructed from tubular pipe, a disposable stopper is positioned at the opening of said one end so as to prevent the injected material from flowing through the opening and into the pipe.
In still another embodiment, the handle is inserted into the cavity of the mold such that the two ends of the mold hold the handle in position.
According to one particular aspect of the invention, the mold is configured to surround a rod-like handle having a substantially circular cross section. The mold has a plane of symmetry along a center plane of the rod handle and is formed of two identical half-portions separated by the plane of symmetry. The mold is constructed so as to permit at least one end of the rod to extend outside of the mold.
The mold has stud-like radially-defined projections disposed at selected distances along the longitudinal direction of the handle. These projections are so shaped and positioned to prevent undercuts and spaced from each other so as to ensure free flowing and uniform distribution of the injected material.
The projections are disposed circumferentially around an inside wall of the mold. The inside wall of the mold may further include raised and/or recessed surfaces shaped and arranged in such a way as to form decorations and/or inscriptions on the to-be-molded protective coat. These surfaces may be dimensioned to extend radially inwardly and engage the surface of the handle placed in the mold so as to form grooves in the protective coat to thereby allow visual inspection of the handle surface.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.